Leaving Certificate Agricultural Science

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Leaving Certificate Agricultural Science
Sheep - 1
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Learning Outcomes...

• In this unit you will learn about...
• Breeds of Sheep and their characteristics.
• Dental Formula.
• Target weights.
• Gestation Period and Oestrous cycle (duration
  length).
• Ram Ewe Selection.
• Mixed Grazing.
• Creep Feeding.
• Breeding Management Programme- Flushing
  Sponging
• Management of the pregnant ewe.
• Management of lamb from birth to slaughter.
• Sheep Dipping and shearing.
• Sheep Housing.
• Wool.

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Sheep Facts

• Lamb weighs
• 3 5 kg at birth
• 30-40kg at slaughter
• Gestation period 149 days (5 Months)
• Oestrous cycle 17 days
• Duration of oestrous 36 hours
• Ruminant
• Phylum Chordata
• Even Toe Ungulates

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DENTAL FORMULA- Sheep

• Incisors, Canines, Premolars, Molars.

0 0 3 3 4 0 3 3
X 2
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Mixed Grazing of Cattle Sheep

• Growth rates increase by 10-15
• Tillering- a denser sward increased DM
  production
• Flush of grass around dung is ate by sheep. This
  is unpalatable to cattle.
• Even recycling of nutrients

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Learning Check...

1. State the length and duration of the oestrous
   cycle.
2. What is length of gestation?
3. Name the phylum that sheep belong to.
4. State the dental formula foe a sheep.
5. What is mixed farming?
6. Give the advantages of mixed grazing.

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Breeds

• Mountain Lowland Breeds.
• Wool/Lamb/Ewe Production
• Degree of prolificy 1,2,3
• Growth rate Conformation
• Blackface Mountain
• Wicklow Cheviot
• Galway
• Suffolk Down
• The Belclare Improver

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Breeds- Classification

• Prolific breeds- Belclare Improver
• Carcass breeds- Suffolk, Texel
• Cross breeds
• Ewe breeds- Galway, Blackface Mountain and
  Cheviot.

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Blackface Mountain

• Mountain Breed
• Ewe Breed
• Small Hardy
• Able to withstand mountain conditions
• Horned
• Wool breeding ewes
• Become prolific if crossed appropriately.
• Mountains over 350m Kerry, Galway, Donegal, etc

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Wicklow Cheviot

• Mountain Breed
• Small
• Not as hardy as blackface
• Able to withstand mountain conditions
• Wool breeding ewes for lowland fattening.
• Mountains Wicklow, Carlow, Kildare, Wexford

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Galway

• Lowland
• Native breed
• Live in a less severe environment
• Big Late maturing
• Wool, Fat lambs hogget mutton breeding ewes

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Suffolk
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The Belclare Improver

• Cross between Galway Finnish Landrace to
  improve prolificy
• X Llynn to improve conformation

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Learning check...

• Name 3 categories of breeds.
• Name 4 breeds.
• Give their characteristics.

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Breeding Strategy

• If flock is inadequate or poor quality Replace
  either ewes or RAMS- Cheaper to replace
• 1 RAM 50 Ewes naturally
• 1 RAM 8/10 ewes Synchronisation

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Selecting Breeds

• Good Carcass
• Good Conformation
• Good prolificy.
• Wool/ewes/meat
• Feed fertility is increased with high quality
  feed

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Ewe Ram Selection

• EWE
• Good Conformation
• Good General Health
• Daughter of Prolific Mother
• Free from hereditary defects
• Good Feet

• RAM
• Good Conformation
• Good General Health
• Performance Tested by dept.
• Very Good Feet

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RAM Selection

• Pure breed
• If ram has been used the previous year and ewe
  labs retained Ram has to go!!!!!
• Insure not Sterile,
• Ram reaches puberty at 6 months

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Ram for Quality

• Ram is half the flock.
• Growth rate
• Conformation
• Killing out
• Leaness
• All are determined by the RAM breed
  (purebred/pedigree)

Pedigree Texel Ram realised 220,000 Guineas Sept
2009
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Ewe for Quantity

• Ewe should be prolific
• Good mothering qualities.
• Flushing of ewe increases number of lambs.
• Reproductive efficiency.
• Belclare Improver

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Time to replace ewe if

• Old.
• Not prolific.
• Udder troubles (mastitis)
• Faulty teeth.
• Under size.
• Lambing difficulties.
• Low milk yield.
• Barren.
• Bad feet.

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Learning Check....

• List 5 factors to be considered when selecting
  breeds.
• Name the factors when selecting ewes and rams.
• Consider the comment that rams are for quality
  and ewes are for quantity.
• When is it time to consider replacing the ewe?

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Gestation

• Seasonally Polyoestrous
• Oestrous Sept-Feb
• Length 17 days
• Duration 36 hours
• Gestation Period 149 days (5 Months)

149 Days
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Oestrous cycle

• Sheep are seasonally polyoestrous.
• This means they come into oestrous repeatedly but
  only over a certain period or season of the year.
• This period is from early September to February
• The length of oestrous is 17 days
• The average duration of oestrous is 36 hours

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Oestrous cycle

• The declining light levels in September act on
  pituitary gland.
• This stimulates Follicle stimulating hormone
  (FSH)
• This in turn stimulates the ovaries to produce
  oestrogen
• This begins the oestrous cycle.

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Preparing Stock For Mating

• Ewes should be in good condition Condition
  Score 3.5-4.0
• High Conception rate results
• Technique Flushing
• Moving sheep onto rich pastures 2 weeks prior to
  mating

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Before Mating

• Two weeks before mating the sheep should receive
  their winter dip (not before 15th September)
• Otherwise the sheep can receive the dip a few
  weeks after mating.
• The whole flock should be dosed for intestinal
  parasites (worms).
• The wool around the tail should be trimmed to
  facilitate service and avoid injury to the ram.

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Flushing

• Ewes are stocked heavily on bare pastures
  25/30/ha before weaning mating
• A couple of weeks before mating nutrition is
  improved by stocking them less heavily 15/18/ha
• More eggs released at ovulation (twins)
• More regular heat periods
• Higher conception rates
• Better attachment to uterus

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Mating

• Eweram 140
• Eweram 110
• Rams must be kept away as they will fight
• Dates kept lambing date
• Marker dye every 17 days- Raddled
• Ear tagged
• 6-8 wks- all should be in lamb
• Suspect ram-cull

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Breeding out of season

• This is a technique used to induce ewes to lamb
  early enough for the lambs to be ready for the
  Easter market
• Prices are highest at this time
• Lambs born from September/October matings will
  not be ready for the easter market.
• Ewes must be brought into oestrous out of season,
  in July or August.

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Breeding out of season

• This involves placement of the progesterone-impreg
  nated sponges.
• When the sponge is removed a single intramuscular
  injection of pregnant mares serum gonadotrophin
  (PMSG) is administered to the sheep.

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Sponging

• Ewes are introduced to the ram in early Sept. for
  8 weeks
• Heat served at different times- lambing
  protracted
• Oestrous can be synchronised. Shorter mating
  lambing periods
• Sponges are impregnated with progesterone into
  the ewes vagina left their for 12 16 days.
• The progesterone blocks the oestrous cycle
• If sponges are removed simultaneously all ewes
  come in oestrus 2 days later are all mated
  together
• All lambs born same time (not protracted)

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Raddling Harness

• Detects mating behaviour in rams.
• Helps predict lambing date.
• Aids in detecting infertile ewes which is
  therefore useful for culling.
• Also identifies infertile ram. (if all ewes show
  3 different colours).
• Colour changes every 17 days.

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Learning Check....

• Explain the following terms
• Synchronisation.
• Flushing
• Sponging
• Breeding out of season.
• Outline the steps involved in preparing the flock
  for mating.
• What is a raddling harness?